The purpose of this study is to improve the treatment of coronary artery disease and angina pectoris. Measurements of narrowed arteries by X-ray, and testing of an adjacent artery for active atherosclerosis by infusing acetylcholine will be performed on patients undergoing cardiac catheterization and angioplasty. At six months patients will undergo repeat catheterization when measurements of the dilated artery will be performed to evaluate any improvement.